Cars 2 G rating appropriate?

I saw the movie yesterday. I was disturbed with how these cars were tortured! (indeed, my inner child with its concern wrapped its paws around the idea of the cars that were killed got fixed) And look at how these cars are consuming martinis! I actually found that funny, but I saw several parents and their little kids get up and leave throughout the movie. I thought maybe this Pixar film deserved a PG13, PG rating? I liked the graphics, animation, and adventure and snippets of humor, but in all, it is DEFIANTLY not my favorite movie. So, what do you think about the movie and what is should be rated?